# US 8,770,788 B2 · Backlight unit, display device, and electronic device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,770,788 B2 - Document ID: US8770788B2 - Status: Granted - Kind: B2 - Application number: 13/276,813 - Filed: 2011-10-19 - Published: 2012-04-26 - Granted: 2014-07-08 - Earliest claimed: 2010-10-21 - Assignees: Semiconductor Energy Laboratory Co., Ltd. - Applicants: Hidekazu Miyairi - Inventors: Hidekazu Miyairi - Web page: https://patentgrep.com/patent/US8770788B2 ## CPC - G02F 1/133603: {with LEDs} - G02B 5/0278: {used in transmission} - G02F 1/133611: {including means for improving the brightness uniformity} - G07F 17/3211: {Display means} - H04M 1/22: Illumination; Arrangements for improving the visibility of characters on dials - H04N 5/66: Transforming electric information into light information (scanning details H04N3/00) - G02F 1/133622: {Colour sequential illumination} - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - G07F: COIN-FREED OR LIKE APPARATUS (coin sorting G07D3/00; coin testing G07D5/00; {handling coins or paper currencies apart from payment activated apparatus G07D; payment architectures, schemes or protocols G06Q20/00}) - H04M: TELEPHONIC COMMUNICATION (circuits for controlling other apparatus via a telephone cable and not involving telephone switching apparatus G08) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A novel structure of a backlight unit where color-scan backlight drive is performed and a color mixture problem can be reduced is proposed. In the backlight unit where color-scan backlight drive is performed, in order not to form a color mixture region by light from a light source, an optical system is provided between the light source and a diffuser sheet so that the light is isotropically spread. Specifically, the distribution of intensity of light in the minor-axis direction is narrowed by the optical system provided between the light source and the diffuser sheet. The distribution of intensity of light in the major-axis direction is made uniform by the optical system. Further, the spread of light from the light source in the minor-axis direction in which a color mixture region is formed is suppressed and luminance on a light-emitting surface in the major-axis direction is made uniform. ## Claims ### Claim 1 A backlight unit comprising: a light source portion comprising a plurality of zonal light source regions; and an optical system adjacent to the light source portion, wherein each of the plurality of zonal light source regions comprises a plurality of light sources of a plurality of colors, wherein the plurality of light sources are arranged in matrix, wherein one of the plurality of zonal light source regions is configured to emit a first light in a period, and a region adjacent to the one of the plurality of zonal light source regions is configured to emit a second light in the period, wherein a color of the first light is different from a color of the second light, and wherein the optical system is configured to narrow a distribution of intensity of a light emitted from each of the plurality of zonal light source regions in a minor-axis direction in any one of the plurality of zonal light source regions. ### Claim 2 (depends on 1) The backlight unit according to claim 1, wherein the optical system is configured to uniform the distribution of intensity of the light emitted from each of the plurality of zonal light source regions in a major-axis direction. ### Claim 3 (depends on 1) The backlight unit according to claim 1, wherein the optical system is a lenticular lens. ### Claim 4 (depends on 1) The backlight unit according to claim 1, further comprising: a diffuser sheet over the light source portion with the optical system interposed therebetween, wherein the diffuser sheet is configured to diffuse a light whose intensity is corrected by the optical system. ### Claim 5 (depends on 1) The backlight unit according to claim 1, wherein the plurality of colors are for a color display. ### Claim 6 (depends on 1) The backlight unit according to claim 1, wherein the plurality of colors comprise red, green, and blue. ### Claim 7 (depends on 6) The backlight unit according to claim 6, wherein the plurality of colors further comprise at least one of cyan, magenta, and yellow. ### Claim 8 (depends on 1) The backlight unit according to claim 1, wherein each of the plurality of light sources is a light-emitting diode. ### Claim 9 A display device comprising: an element substrate; a backlight unit overlapping with the element substrate, the backlight unit comprising: a light source portion comprising a plurality of zonal light source regions; and an optical system between the element substrate and the light source portion, wherein each of the plurality of zonal light source regions comprises a plurality of light sources of a plurality of colors, wherein the plurality of light sources are arranged in matrix, wherein one of the plurality of zonal light source regions is configured to emit a first light in a period, and a region adjacent to the one of the plurality of zonal light source regions is configured to emit a second light in the period, wherein a color of the first light is different from a color of the second light, and wherein the optical system is configured to narrow a distribution of intensity of a light emitted from each of the plurality of zonal light source regions in a minor-axis direction in any one of the plurality of zonal light source regions. ### Claim 10 (depends on 9) The display device according to claim 9, wherein the optical system is configured to uniform the distribution of intensity of the light emitted from each of the plurality of zonal light source regions in a major-axis direction. ### Claim 11 (depends on 9) The display device according to claim 9, wherein the element substrate comprises a plurality of zonal display regions, wherein the plurality of zonal display regions overlap the plurality of zonal light source regions, and wherein a color of one of the plurality of zonal display regions is same as a color of one of the plurality of zonal light source regions. ### Claim 12 (depends on 9) An electronic device comprising the display device according to claim 9. ### Claim 13 (depends on 9) The display device according to claim 9, wherein the optical system is a lenticular lens. ### Claim 14 (depends on 9) The display device according to claim 9, further comprising: a diffuser sheet over the light source portion with the optical system interposed therebetween, wherein the diffuser sheet is configured to diffuse a light whose intensity is corrected by the optical system. ### Claim 15 (depends on 9) The display device according to claim 9, wherein the plurality of colors comprise red, green, and blue. ### Claim 16 A backlight unit comprising: a light source portion comprising a plurality of light source regions; and an optical system adjacent to the light source portion, the optical system comprising a lens, wherein each of the plurality of light source regions comprises a plurality of light sources of a plurality of colors, wherein the plurality of light sources are arranged in matrix, wherein the lens is configured to narrow a distribution of intensity of a light emitted from each of the plurality of light source regions in a longitudinal direction of each of the plurality of light source regions, wherein the plurality of light source regions include a first light source region, a second light source region, a third light source region between the first light source region and the second light source region, and wherein the first light source region, the second light source region, the third light source region are configured to emit lights of different colors in the plurality of colors from each other in the same period. ### Claim 17 (depends on 16) The backlight unit according to claim 16, wherein the lens is configured to uniform the distribution of intensity of the light emitted from each of the plurality of light source regions in a lateral direction. ### Claim 18 (depends on 16) The backlight unit according to claim 16, wherein a lateral direction of lens corresponds to the longitudinal direction of each of the plurality of light source regions. ### Claim 19 (depends on 16) The backlight unit according to claim 16, wherein the lens is a lenticular lens. ### Claim 20 (depends on 16) The backlight unit according to claim 16, further comprising: a diffuser sheet over the light source portion with the optical system interposed therebetween, wherein the diffuser sheet is configured to diffuse a light whose intensity is corrected by the lens. ### Claim 21 (depends on 16) A display device comprising: an element substrate comprising a display region; and the backlight unit according to claim 16. ### Claim 22 (depends on 21) An electronic device comprising the display device according to claim 21.